Challenges of Slurry Distribution System Simulation for Fumed Silica Based Slurry. Pete Bridger JSR Micro NV

Transcription

1 Challenges of Slurry Distribution System Simulation for Fumed Silica Based Slurry Pete Bridger JSR Micro NV

2 Contents Background Test Configuration SDS Design Results of Levitronix & Diaphragm Pumps Impact of Filtration on LPC Impact of Slurry Mixing / Agitation Effect of Nitrogen Purging Conclusions 1

3 Background Slurry suppliers are often asked how their slurry should be handled in a slurry distribution system (SDS). Slurry suppliers often do not have experience of circulating slurry in distributions systems for long periods of time without cleaning. This study demonstrates how JSR simulated a distribution system to understand how key parameters affect the slurry quality and how Levitronix pumps provide an advantage over traditional pumps.

4 Test Configuration Tank : 400L Natural Polypropylene Piping : 1 inch Polypropylene Pump : Levitronix BPS-3 with cooling manifold Mixing / Agitator Speed : 100rpm continuously ON / OFF Filtration : None Nitrogen Blanket : 99.99% (No humidification) Slurry : Commercial Fumed Silica Oxide Slurry (Single Lot) Slurry Volume : 100Kg Sample Volume : 1L Metrology Particle Size : Horiba LA-950 Laser Diffraction (Median D50) Particle Counting : AccuSizer 780APS (>0.56um & >1.02um) 3

5 SDS Simulation with Levitronix Pump Tank = 400L Slurry Volume = 100L Filter Housing With or w/out filter Mixer ON 100rpm or OFF Levitronix BPS-3 Pump or Diaphragm Pump

6 Levitronix BPS-3 with Air Cooling Line * The slurry did not change between pump cooling and without pump cooling. 5

7 Intensity Particle Size Distribution 25 Colloidal Silica Slurry 20 S31- D08 // mean 179nm, max 440nm Commercial Fumed Silica Slurry Commercial Fumed Silica // mean 178nm, max 427nm Commercial Colloidal Silica // mean 88nm, max 195nm *Horiba LB550 - Dynamic Light Scattering Particle Size (nm) The bulk of the fumed silica slurry distribution is <500nm (0.5um) 6

8 LPC : AccuSizer 780APS Commercial Fumed Silica Slurry Using Single Particle Optical Sensing Larger Particles are present >0.56um 7

9 Magnified Scale LPC : AccuSizer 780APS Very low large particle count >1.02um 8

10 Particle Size Comparison Levitronix and Diaphragm Pump USL Median Particle Size vs. 7 Days Flow 16L/min No Filtration No Mixing N 2 Purging LSL Median Levitronix with Pump Cooling Diaphragm Pump No change in median particle size 9

11 Comparison Levitronix and Diaphragm Pumps LPC >0.56um vs. 5'000'000 4'500'000 4'000'000 3'500'000 3'000'000 UCL LPC Levitronix >0.56 with Pump Cooling Diaphragm Pump 7 Days Flow 16L/min No Filtration No Mixing N 2 Purging 2'500'000 2'000'000 1'500'000 1'000' ' Diaphragm pump increases the LPC >0.56um while Levitronix pump remains stable 10

12 Counts / ml Comparison Levitronix and Diaphragm Pumps 500' ' ' ' ' ' ' ' '000 50'000 0 LPC >1.02um vs LPC Levitronix >1.02 with Pump Cooling Diaphragm Pump 7 Days Flow 16L/min No Filtration No Mixing N 2 Purging A large increase in LPC >1.02um is seen with the diaphragm pump 11

13 Filtration Impact A test was set up to simulate the impact of different filters pore size on Large Particle Count (LPC) reduction. A high LPC slurry was created then filters of different pore sizes were used to see the impact on the LPC. For example, a 10um filter was used then the LPC was measured. This filter was replaced with a 5um filter and the LPC measured. Generation of LPC >1.02 Installation of 10um Filter Exchange of 10um Filter with 5um Filter Exchange of 5um Filter with 1um Filter 12

14 Counts / ml Effect of Filtration on High LPC >1.02um LPC >1.02um Filtration No Filter 10um Filter 5um Filter 1um Filter Time um, 5um and 1um filters all reduce the LPC >1.02um (Median PSD and LPC>0.56um were not effected by this filtration) The 1um filter (same media as POU filter) brings the LPC back close to baseline. 13

15 Median Particle Size(nm) Impact of Mixing / Agitation Impact of Mixing on Median PS UCL Levitronix Pump Mixing 100rpm No Filtration N 2 Purging LCL Median Particle Size also increased when the slurry tank is mixed. The increase is believed to be due to excessive shearing during mixing. Test was repeated with a larger volume of slurry (Confirmation Run). 15

16 Counts / ml Counts / ml Impact of Mixing / Agitation Levitronix Pump Mixing 100rpm No Filtration N 2 Purging Impact of Mixing on LPC >0.56um 7'000'000 6'000'000 5'000'000 4'000'000 3'000'000 UCL 2'000'000 1'000' Impact of Mixing on LPC >1.02um 90'000 80'000 70'000 60'000 50'000 40'000 30'000 20'000 USL 10' Slurry Mixing has a big impact on LPC. 14

17 Impact of Nitrogen Purging ph drops without Nitrogen purging 16

18 Counts / ml Particle Size(nm) Counts / ml '000 Mixing / Agitation Confirmation Run Median PSD vs LPC >1.02um vs. 7'000'000 6'000'000 5'000'000 4'000'000 3'000'000 2'000'000 1'000' LPC >0.56um vs ph vs. Levitronix Pump No Filtration Mixing 100rpm No N 2 Purging 50'000 40' ' ' ' ph drops without N 2 purging The results of creating too much shear from mixing are confirmed 17

19 Conclusion Slurry distribution systems can be simulated on a small scale to determine the best conditions to handle the slurry. The Levitronix pump gave much lower levels of Large Particle Counts compared to Diaphgram pump. High mixing speeds result in high sheer and splashing / drying of the slurry which gives increased particle count. Mixing slurry without nitrogen purging can result in an absorption of CO 2 and change in ph. 18